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Friday, September 12, 2014

Paphiopedilum dayanum

That fringe of long silky hairs. Paphiopedilum dayanum always gets a second look from me. True, there are other Paphs with hairs, but this is the only one in our collection that triggers a grooming impulse. What other orchid has petals that need combing?

Paphiopedilum dayanum is one of those select plants that grows on Borneo's Mt. Kinabalu and nowhere else. Like many terrestrial orchids it occupies a specialized micro-habitat. Phillip Cribb reports that it grows in leaf litter under bamboo and at the base of trees on steep ridges around the mountain at 300 to 1450 meters elevation.

Why the the hairs on the petals? They may be an adaptation to attract flies that can pollinate the flowers. Hairs, warts, aphid-like bumps. Carrion colored flowers. Together, these comprise a syndrome associated with fly pollination.

Paphiopedilum dayanum has been trouble-free for us. It seems fine with temperatures on the warm side of intermediate (60 to 62º night minimum) in a shady greenhouse in a mixture of fine fir bark, chopped moss, charcoal and perlite.

Thursday, September 11, 2014

Lycaste schilleriana var. rosea

Among all of our Lycaste species, this could be my favorite. Of the two or three dozen Lycaste species in cultivation, most fall within the traditional spring floral color spectrum--pinks, yellows, whites. Not this one.

This is Lycaste schilleriana var. rosea. I love the deep olive green of the sepals. They are olive on the exterior and bronze on the inside.

Even more remarkable is the extraordinary length of its sepals. Each sepal is about 3 inches long, giving L. schilleriana the widest flowers in the genus.

The buds look like elongated beaks.

Lycaste schilleriana var. rosea likes a greenhouse at the cool end of the intermediate temperature spectrum. For now, our plant resides in our shadiest most humid greenhouse right next to the wet wall, where the summer daytime temperature maxes out at about 83º. If the current warming trend continues, we may have to move it to the Tropical High Elevation House.

Lycastes are pollinated by Euglossine bees. Lycaste schilleriana is known from Panama and Colombia where it grows as a lithophyte at around 1400 meters elevation.

Thursday, September 4, 2014

Identifying our Acineta

Great news: we have a name on our mystery Acineta. And it's not erythroxantha, the name that was on the label when we received it from a Panamanian grower. In order to make the determination, it was necessary to dissect a couple of flowers and send photographs to Dr. Günther Gerlach at Münich Botanical Garden. He was very specific about which floral parts he needed to see. Here is what I sent him.

Shown above, I've removed two lateral sepals and one of the lateral petals in order to show the lip in side view. Each side of the lip has two deep incisions, creating a side lobe. The column is white and partly hidden by the lip.

Next, I made a longitudinal cut through the lip to show it in cross section. The interior has blood red spots. You can see the callus, chair-shaped and white in cross section.

Then, I removed a second flower and cut off everything but the the lip and the ovary. Above, you can see the lip, face up. It is shaped like a shallow scoop. Just above the broadly U-shaped edge of the lip is the callus, which is wide and thin seen from above. The lip and callus are important diagnostic features.

The underside of the lip.

The pollinarium, including two pollinia and a sticky orange viscidium.

This must have been an easy call for Dr. Gerlach, who described this species, Acineta mireyae, in 2003. Additonal photos appear on his amazing Stanhopeinae image data base, where you can compare A. mireyae with some closely related Central American species, Acineta sulcata and Acineta sella-tucica. In fairness to the grower from whom we purchased our plant, I should mention that it was shipped to us in 2002, before publication of the epithet mireyae. Our thanks to Dr. Gerlach for solving this mystery!

Tuesday, September 2, 2014

Open at last... But what is it?

It's not very often that we flower an Acineta, so there has been tremendous anticipation as the spike of this Acineta erythroxantha has elongated to an astonishing 28 inches. Bud development has been agonizing. ('Slow as Christmas' is the phrase around here.) But at last we have open flowers. And a surprise...

This isn't actually Acineta erythroxantha at all, as the label would indicate. The lip is very different. We received this plant in 2002 as A. erythroxantha from a Panamanian source. Could this be the Panamanian species, Acineta mireyae?

For an answer, I'm turning to Dr. Mark Whitten at University of Florida-Gainesville and Dr. Günther Gerlach at Münich Botanical Garden, rockstars of Euglossine bee-orchid research. Acineta identification is tricky and I want a definitive answer. Dr. Gerlach is the author of the original 2003 publication of  A. mireyae, so I'm sending pictures of these flowers, dissected. We'll see what he says.

Acineta belongs to the Stanhopeinae subtribe, and like Stanhopea, they are pollinated by Euglossine bees of the genus Euplusia.

The waxy fragrant flowers are carried on a pendant raceme. The sepals and petals form a hood around the column, creating a tunnel for the bee to enter. The bee obtains the fragrance by scratching at the base of the lip inside the tunnel. As the bee backs out, the viscidium of the pollinarium is stuck to the bee's scutellum. If the bee enters another Acineta flower, the pollinia are placed on the stigma as the bee backs out, and thus the flower is pollinated.

Wednesday, August 27, 2014

Saving Monkeyface and its Habitat

Monkeyface Orchid (Platanthera integrilabia) is one of our prettiest native orchids, though if you've seen it you can consider yourself lucky. Although it ranges from the southeastern to the south central United States, Monkeyface Orchid is rare throughout its range, occupying a very limited wetland niche: seepage bogs or slopes, and streamheads in open forests. There are only eight known populations in the Georgia Piedmont, all of them decreasing in size and vigor. Urban encroachment, large scale conversion of habitat into timber production and competition from invasive exotic or overstory plants have made Platanthera integrilabia a threatened species in Georgia and a candidate for protection under the Endangered Species Act.

The good news is that some constructive action is underway to protect Monkeyface Orchid in Georgia. Four sites in Georgia are the focus of a new conservation project funded by the National Fish and Wildlife Foundation's Five Star/Urban Waters Grant Program. It will be conducted by ABG in partnership with a number of other organizations.* The goal of the project is to restore the habitat and reintroduce plants grown from seed (collected on site and germinated in ABG's lab) into their restored habitat.

Restoration will take time and lots of hard work. Matt Richards, ABG's Conservation Coordinator, is spearheading the project for ABG. According to Matt, these sites are under constant pressure from illegal trash dumping, competition from invasive exotic plants, closure of the forest canopy and herbivory. The first step will be to map and survey each site. Next, a management plan will be developed for each site, taking into account the threats specific to each site, with the immediate goal of protecting the existing plants. Some sites may need deer fencing. At others, saplings will be removed and mature trees girdled to remove competition and open the canopy. Invasive exotic plants will be removed; garbage will be hauled away.

Monkeyface Orchid flowers in August. Capsules mature in about three months. Matt will collect capsules and germinate the seed in ABG's lab. The germination rate in cultivation, according to Matt, is low compared with that of tropical orchids, only about 50%. In the fall, Matt will plant deflasked seedlings in beds in our nursery, where they will remain for about a year.

Once the habitat has been restored and a management plan enacted, Matt and his associates will reintroduce seed propagated plants. At this stage the goal will be to establish flowering sized plants that produce seed. Fall is the season that Matt prefers for outplanting of year-old seedlings. It takes another two years for the plants to flower. Habitat management will continue in the meantime, and the sites will be monitored.

In the United States many threatened ecosystems occur in and around urban areas, and they are a high priority for restoration despite their often degraded condition and remnant status. "It's significant that we have wetlands and natural areas in Metro Atlanta that harbor rare plants like Monkeyface Orchid," said Dr. Jenny Cruse-Sanders, Vice President for Science and Conservation at ABG. It is important that we focus our efforts and expertise towards conserving this species in our own community."

Congratulations to our conservation team on this exciting new project!

*NFWF Five Star/Urban Waters Restoration Partners:
Atlanta Botanical Garden
Georgia DNR Non-Game Conservation Section
Georgia State Parks
Big Canoe POA
Sewanee Mountain Preserve
The Dunn Family
Rock Spring Farms
Georgia Environmental Restoration Professionals
Georgia DOT
Georgia Power
Chattahoochee Nature Center
Lovett School
Grady High School
Peachtree Garden Club

Monday, August 11, 2014

Crested Yellow Orchid

Monday was a gorgeous day for photographing Fringed Orchids (Platanthera) in our nursery. Of the 14 species of Platanthera found in Georgia, eight are in cultivation in our nursery plus a number of hybrids with a confusing array of intermediate characteristics. Fortunately, Matt Richards, our Conservation Coordinator, happened by and brought me up to speed. Matt knows them all. Not only does he conduct our conservation field work with Platanthera, he also propagates a number of them from seed in our lab and grows them in our nursery. He began by comparing the different species.

Crested Yellow Orchid (Platanthera cristata), pictured above, is one of a handful of yellow/orange Platanthera found in Georgia. In Georgia it is not as widespread or as common as Yellow Fringed Orchid (Platanthera ciliaris), but it has been found in at least 13 counties. Like P. ciliaris, it grows in moist open pinelands, wet meadows, roadsides and ditches. P. cristata starts flowering a bit before P. ciliaris, but there is some overlap in their flowering seasons. Where they occur together they often hybridize.

Even from a distance, it is easy to distinguish between the two species. In overall dimensions and flower size, P. cristata is about half the size of P. ciliaris. The inflorescence is more cylindrical in shape. A closer comparison reveals that P. cristata's spur is about as long as the flower's lip, while P. ciliaris' spur is much longer than its lip. In P. cristata, the column forms a beak, or downward hook over the lip. The lateral petals are fringed over the entire margin, and not just the tips, as in P. ciliaris.

Crested Yellow Orchid grows in wetlands outside of Georgia, too. Its range follows the east coast of the US from New Hampshire south to Florida and across the southeast to Texas. Platantheras are among our most beautiful native orchids and a fascinating component of our disappearing wetlands.

Thursday, August 7, 2014

Yellow Fringed Orchid

It might surprise you to learn how widespread this spectacular orchid is. The range of Yellow Fringed Orchid (Platanthera ciliaris) occupies nearly the entire eastern half of North America. But it is limited to wetland habitats, a potential Achilles' heel, since these habitats have been shrinking in percent area, especially during the last fifty years.

Platanthera ciliaris, with its spectacularly fringed lip and long spur, is familiar to many residents on the US east coast. In the southeastern states it grows in acidic soils in longleaf pine savannahs, wet open meadows, forests, seepage slopes and road edges. In the northern part of its range it grows in bogs and wetlands. Like many wetland species, it depends on fire to maintain an open canopy.

Platanthera ciliaris is pollinated by large butterflies, especially swallowtails, who feed on nectar at the bottom of the flower's spur. When a butterfly probes for nectar with its long tongue, the viscidium of the pollinarium is stuck to the insect's compound eye.

A few fascinating studies have found evidence for different pollination ecotypes in Yellow Fringed Orchid. An ecotype is a locally adapted population that is genetically different from other populations. The studies found that in the mountains, the short-tongued butterfly, Papilio troilus, was the predominant and most effective pollinator; and in the coastal plain, the long-tongued Papilio palamedes was the predominant, but less effective pollinator. The coastal plain butterflies were less effective pollinators because their longer tongues kept their bodies at a distance from the pollinarium. The research suggested that the long-tongued coastal plain butterflies were exerting selection pressure for longer spurs on the coastal plain populations of Platanthera ciliaris.

ABG's Conservation Coordinator, Matt Richards, says that Platanthera ciliaris is easy to germinate in the lab, fast growing and produces vigorous seedlings. Some of the plants that Matt produced are in the nursery and are flowering now.

Friday, August 1, 2014

Beautiful Things

Orchid fruits are every bit as beautiful as orchid flowers, I think. I removed an unripe Cattleya fruit last week and showed it to some of our visitors. You can see the brown withered flower still attached to the far end. In the photo below, peaking out from among the withered petals, is the oval shaped stigmatic surface at the end of the column.
An orchid fruit is a capsule, packed with minuscule seeds.

Above, I've cut it into cross sections to show its symmetry. The capsule is divided into three carpels. When a capsule is fully ripe, it splits lengthwise, down the midline of each carpel. Orchid capsules come in a huge variety of sizes and shapes. Not all of them are large and fleshy like this Cattleya capsule, but they share the same basic arrangement. Beautiful, isn't it?

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